On Tue, 8 Jun 2010 20:14:29 -0400 Pinnacle <pinnc...@rochester.rr.com> wrote:

:>same thing.  Authorized code can hack MVS, unauthorized code can't. 

The security exposures exist when the authorized code "trusts" an address
passed by unauthorized code.

Authorized code cannot trust anything provided by unauthorized code. That
means going into the callers key when fetching or modifying storage based on
an address provided and should the caller pass the address of a protected
control block, such as a TCB address, verifying that the address is in fact of
a TCB and it is where such service is allowed. Should an exit be allowed, such
as a DCB OPEN exit, SYNCH back to problem state and key must be used. And,
obviously, no workareas of the authorized routine are allowed to be in a key
that allows the unauthorized routine ability to update (and, perhaps, even
fetch). 

--
Binyamin Dissen <bdis...@dissensoftware.com>
http://www.dissensoftware.com

Director, Dissen Software, Bar & Grill - Israel


Should you use the mailblocks package and expect a response from me,
you should preauthorize the dissensoftware.com domain.

I very rarely bother responding to challenge/response systems,
especially those from irresponsible companies.

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